JPS6144434B2 - - Google Patents

Abstract

PURPOSE:To realize the small size and small thickness plus the low cost for the device by storing the preheating mechanism utilizing the radiation pipe into the dead space produced by giving the contrivance to the arrangement of the mechanism part. CONSTITUTION:Both transmission mechanism part A and recording mechanism part B are arranged in such way that almost the right angle may be formed between the axial line of the original carrier direction and the axial line of the recording paper carrier direction. As a result, extra space S is produced at the side of part B based on the difference between original length direction measurement lA of part A and recording paper width direction measurement lB of part B. Then radiating heat pipe 6 of substrate 2 is set to secure the parallel contact to the row of heat generation element 3 and over nearly the full length of the longer side to substrate 2, and the end of spece S side is extended to be protruded into space S. Then radiation fin 7 is attached to the protrusion end part to ensure the natural convection cooling, and furthermore wind fan 8 is provided to perform the forced convection cooling.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording type facsimile apparatus.

Conventionally, various methods have been used to configure the recording section of a facsimile apparatus, such as a thermal recording method, an electrostatic recording method, a discharge destruction recording method, and an inkjet recording method.

Among these, the thermal recording method has a simpler process and equipment configuration than other methods, does not generate solvent vapor or bad odors, is compact and easy to maintain, and uses recording paper (heat-sensitive recording paper).
In recent years, it has become the mainstream method for configuring the recording section of facsimile machines because it is relatively inexpensive, has paper quality similar to plain paper, and has low running costs.

The outline of thermal recording is explained with reference to FIGS. 1a and 1b. A large number of heating elements 3 are arranged in the longitudinal direction (main scanning direction) on one side of a horizontally long substrate 2, which is generally made of ceramic.
are arranged in a row to form thermal head 1, and that head 1
The recording paper P is conveyed at a predetermined speed in one direction (sub-scanning direction) orthogonal to the head element row while the thermosensitive recording paper P is brought into close contact with the surface of the head element side using a pressing means 4 such as a rubber roller.

The recording paper P is conveyed in the sub-scanning direction, and each element 3 of the head 1 is controlled by a control circuit (not shown).
By performing a main scan that selectively generates heat (joule heat) according to the received information signal, the portion of the recording paper that has passed through the element that selectively generates heat is thermally colored, and the received information signal is applied to the P side of the recording paper. Corresponding colored images (characters, symbols, drawings, etc.) are recorded in sequence. The recorded image is a visible permanent image,
In principle, the subsequent development and fixing treatment of the recording paper is unnecessary.

Incidentally, in the case of a thermal recording type facsimile apparatus, some kind of heat radiating means is provided to radiate the heat accumulated in the thermal head substrate.

That is, only a portion of the heat generated in each element 3 of the thermal head 1 is consumed for coloring the recording paper, and most of it is conducted to the substrate 2 and raises the temperature of the substrate 2. When recording is performed continuously for a long time, at high speed, or when the area of the image area is large (for example, there are many solid black areas), heat accumulation in the substrate 2 increases and the temperature of the substrate 2 causes the coloring of the recording paper. The temperature rises even higher than the temperature, and as a result, so-called capri and trailing occur in recorded images, resulting in a decrease in image quality.

Therefore, a means is provided to release the heat stored in the board 2. Conventionally, a heat sink or heat radiation fin made of aluminum or the like is attached to the board 2 to increase the heat capacity and heat radiation area, and a forced cooling fan or the like is provided. However, in order to radiate the large amount of heat generated during long-time recording, high-speed recording, etc. (sometimes reaching several hundred watts) without any problem, cooling means such as the heat sink and heat dissipation fins must be made larger. I needed to. There are two types of thermal heads: thick-film type and thin-film type. The former is cheaper than the latter, but requires two to three times more recording energy and therefore stores more heat. Therefore, the heat dissipation means of the thick film type thermal head is particularly elaborate.

Therefore, in the conventional thermal recording type facsimile apparatus, the large heat dissipation means has been one of the major obstacles in making the apparatus more compact and lightweight. In addition, when forced cooling is performed using a fan, it is necessary to give sufficient consideration to the air flow, which creates constraints on the arrangement of various components of the device, and limits the degree of freedom in designing for compactness. Ta.

The present invention has been proposed in view of the above, and relates to a thermal recording type facsimile device.By devising the heat dissipation means of the thermal head, the entire device can be made more compact, thinner, lighter, and lighter than conventional devices.
The purpose is to reduce costs, etc.

That is, the present invention provides a thermal recording type facsimile device in which a heat pipe is disposed in contact with the thermal head substrate of the thermal recording mechanism along its length, and a radiator is provided at the extended end of the heat pipe to transmit information through the heat pipe. The heat of the thermal head substrate that is transferred to the thermal head is naturally or forcedly radiated.

Heat pipes themselves have excellent heat transfer properties (thermal conductivity: more than 100 times that of copper), and by using them as a heat dissipation means for the thermal head board as described above, the heat dissipation of the thermal head board can be effectively achieved. In addition, the heat pipe used can be small and lightweight, making the entire heat dissipation means compact, making the entire facsimile device as compact, thin, and lightweight as possible.・It is possible to reduce costs, etc.

The illustrated example will be explained below. FIGS. 2 and 3 show examples of the general arrangement of internal mechanisms of conventional facsimile machines.

The internal mechanism of a facsimile machine can be broadly divided into
There is a mechanism section that reads and transmits the original information to be sent to the other party (hereinafter referred to as the "transmission mechanism section"), and a mechanism section that receives the information on the transmitted manuscript from the other party and records it using the above-mentioned thermal method etc. (hereinafter referred to as the "recording mechanism"). It consists of As shown in FIG. 2, a conventional facsimile device has a transmission mechanism section A (details omitted in the figure) and a recording mechanism section B (details omitted in the figure) on the left and right, and an axis in the document conveyance direction and an axis in the recording paper conveyance direction. are arranged parallel to each other and the entire structure is covered by an exterior case 5, or as shown in Fig. 3, both mechanism parts A and B are arranged in front and behind each other, and the axes of the document and the recording paper in the conveyance direction are substantially aligned. are arranged in series, and the whole is covered with a case 5.

In FIGS. 2 and 3, 6 indicates a document, 51 and 52 indicate an inlet and an outlet for the document, and 53 indicates a recording paper outlet.

Although the device shown in FIG. 2 allows the overall thickness (height) of the device to be relatively thin, since the frontage of the device is wide, the space occupied by the device in the office becomes substantially large.

The one in Figure 4 has a narrower frontage, but is longer in depth and has a thicker overall thickness, so it lacks smartness and has an unsightly appearance.

4 and 5 show an embodiment of the present invention, and in the case of this embodiment, the arrangement of the transmitting mechanism section A and the recording mechanism section B is different from that of the conventional apparatus shown in FIG. 2 or 3. When viewed from the front side of the apparatus, the transmitting mechanism section A is arranged with its axis in the document conveying direction in the front-rear direction, and the recording mechanism section B is arranged to the right of the transmitting mechanism A, with its axis in the recording paper conveying direction facing the above-mentioned document conveying direction. oriented in a relationship substantially perpendicular to the direction axis, and recording mechanism section B.
The front end surface of the device is arranged so that the end surface of the transmitting mechanism section A on the front side of the device substantially coincides with the end surface of the transmitting mechanism section A on the front side of the device. With this arrangement, based on the difference between the document length direction dimension l A of the transmitting mechanism section _A and the recording paper width direction dimension l _B of the recording mechanism section B, the side of the recording mechanism section B opposite to the front side of the apparatus is There is a symbol S between the end face and the back of the device cover 5.
An extra space shown by is generated.

Therefore, the device of this example utilizes the above-mentioned extra space S, and incorporates a heat dissipation means described below into this space. That is, the heat pipe 6 is connected to the heating element 3 over almost the entire length of the thermal head board 2.
The end portion of the heat pipe 6 on the margin space S side is extended to project into the space S. A heat dissipation fin 7 is attached to the protruding end portion to provide natural convection cooling, or a blower fan 8 is further provided for the heat dissipation fin 7 to perform forced convection cooling.

When the heat dissipation means is configured as described above, the heat stored in the substrate 2 is absorbed almost uniformly and quickly from each part in the longitudinal direction due to the excellent heat transfer characteristics of the heat pipe 6, and reaches the heat dissipation fin 7 at the end of the heat pipe through natural convection. is efficiently radiated by forced convection by the fan 8. In this case, a temperature sensor such as a thermistor is attached to the substrate 2 to detect the substrate temperature, and when the substrate temperature is below the coloring temperature of the recording paper, the fan 8 is not operated and heat is dissipated by natural convection, allowing continuous recording for a long time. When the substrate temperature rises and approaches the color development temperature of the recording paper, it is preferable to automatically operate the fan 8 and switch to forced convection cooling. In this way, the substrate temperature can always be maintained at a substantially constant appropriate level during continuous recording, and image density unevenness due to fluctuations in the substrate temperature can be prevented.

(1) As mentioned above, the heat pipe 6 efficiently absorbs the heat of the substrate 2 from its longitudinal parts due to its excellent heat transfer characteristics and transmits it to the extended end of the heat pipe. Therefore, by providing the heat dissipation fins 7 at the extended end, efficient cooling becomes possible. Further, the heat pipe 6 itself has a small volume and is also light in weight. Therefore, the heat dissipation structure itself can be made more compact than the conventional case where a heat sink or a heat dissipation fin is provided on the board to dissipate heat, and the weight can be reduced to, for example, 1/2 or less. Further, even in the case of a thick film type thermal head, the heat dissipation structure described above can sufficiently dissipate heat without any problem.

(2) An extra space S, which is a dead space, is created by the arrangement of the above-mentioned transmitting mechanism section A and recording mechanism section B, in which the heat dissipation fin 7 disposed at the end of the heat pipe 6 and the fan 8 forming a pair therewith are arranged. If the heat dissipation mechanism is housed inside the device, the heat dissipation mechanism can be neatly accommodated without taking up any space or wasted space inside the device.

(3) Also, due to the above-mentioned special arrangement of the transmitting mechanism section A and the recording mechanism section B, the frontage of the apparatus can be made relatively small.

Therefore, the entire thermal recording type facsimile apparatus can be made more compact, lighter, and lower in cost than conventional ones, and is thus effective and suitable as an improvement to this type of apparatus.

Note that the heat pipe 6 may be brought into close contact with the substrate 2 by pressing against the outer surface of the substrate 2 as shown in FIG. 1a, but in order to improve heat conduction efficiency,
If the thickness of the substrate 2 is thick, it is disposed half-embedded or completely embedded in the substrate 2, or
It is preferable to attach a member having good thermal conductivity, such as an aluminum alloy, to the member and dispose the member half-embedded or completely embedded in the member. Furthermore, in order to reduce the heat transfer resistance at the joints of each member such as the substrate 2 and the heat pipe 5, the substrate 2 and a member with good thermal conductivity, the member and the heat pipe, or the heat pipe 5 and the heat dissipation fin, etc. For example, conductive grease may be applied to these joints.

The number of heat pipes 6 is not limited to one, but a plurality of heat pipes may be provided. If a variable conductance type heat pipe is used, in the case of a head where the element 3 generates relatively little heat, the temperature of the head board can be controlled within the desired temperature range without installing a temperature sensor or fan 8, and the problem of heat radiation can be eliminated. .

The heat radiator is not limited to the illustrated fins 7, but may be other types such as a water-cooled heat radiator.

On the other hand, when the device is first used, the head substrate 2 is in a cold state, and the cold is particularly large in winter or in cold regions. Therefore, for a while after first using the printer, the overall density of the recorded image remains low. This is because when the lid is closed and the power applied to each element 3 is constant, the color density of the recording paper becomes higher as the temperature of the substrate 2 is higher, and becomes thinner as the temperature of the substrate 2 is lower.

Therefore, as a preventive measure to prevent this, the heat pipe 6 is placed at the above-mentioned extension end of the heat pipe 6 in the opposite direction to the heat dissipation fin 7.
It is preferable to provide a heat source 9 such as a heater for preheating, and to generate heat from this when the main switch of the device is turned on, for example. As a result, the entire length of the heat pipe 6 is quickly heated, and the entire length of the substrate 2 is quickly preheated to a uniform temperature. This preheating of the substrate 2 makes it possible to obtain images with appropriate density from the beginning. Then, the temperature sensor detects the temperature rise of the substrate 2 due to the turning on of the heat source 9, and when the temperature rises to an appropriate temperature, control is performed to turn off the heat source 9.

Conventionally, the substrate 2 has been preheated by installing a heater under the head substrate, but in order to uniformly preheat the entire substrate 2, a large heater with a large area is required. In the present invention, a heat pipe 6 provided for heat dissipation is used, and if a heat source 9 is provided at a part such as the end of the pipe 6 and the heat pipe 6 is heated, the substrate 2 can be heated due to the characteristics of the heat pipe. It is possible to quickly and uniformly preheat the entire body, and it is possible to construct a preheating mechanism that does not take up much space and is low in cost.

[Brief explanation of the drawing]

Figure 1a is a schematic explanatory diagram of thermal recording, Figure 1b
2 is a plan view of a thermal head, FIGS. 2 and 3 are external oblique views of a conventional device, FIG. 4 is an external oblique view of an apparatus according to an embodiment of the present invention, and FIG. 5 is a plan view showing the arrangement of various parts. 1 is a thermal head, 3 is a heating element, 4 is a pressure roller, 8 is a cooling fan, and 9 is a preheating source.

Claims (1)

[Claims] 1. In a thermal recording type facsimile device, a heat pipe is arranged in contact with the thermal head substrate of the thermal recording mechanism along its length, and a radiator is provided at the extended end of the heat pipe, so that heat is transferred through the heat pipe. A thermal recording type facsimile device characterized by natural heat radiation or forced heat radiation from a thermal head board.